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The Ultrapower UP-S6AC is the bigger brother to my favorite charger, the Ultrapower UP-S6AC. It is bigger than the UP-S6 because the AC adapter is built in. You just plug in straight to the power 100-240V outlet. But you still retain the capability to charge with a 2-4S LiPo (7-17V). It has 6 ports capable of Micro Losi, Molex PIcoblade/MCX, JST-PH/MCPX, and JST-RCY.

You use the “Select” button to select the setting you want to change and the “Setting” buttons to select the value for the setting. Then you press and hold the “Select” button to save the settings.

Comparing the UP-S6AC and the UP-S6, you can see that there’s a substantial difference in size as well as weight. So it would seem that the UP-S6AC is primarily for home use and then you can use it occasionally on the field. The UP-S6 is primarily for the field and but you can charge occasionally at home.

When you start thinking (fantasizing?) of being a drone racer, you will want to know how fast you are around your home track: You need a lap timer to record the time elapsed from the time you leave the starting gate to the time you pass it again. There are usually two ways of doing this: attaching a transponder (additional equipment) or using the RF signal of the VTX (no additional equipment). Needless to say, we will be doing the latter approach.

The key component is the RX5808 module which is the heart of most, if not all, video receivers in the market. The module receives the VTX signal and converts it to audio and video. It also measures and provide the signal strength (RSSI value). What the lap timer does is to compare the RSSI with a set threshold. If the RSSI value is above the threshold, the corresponding drone is considered passing a finish gate and the time elapsed is recorded.

There are two maybe three active lap timer projects online: Chorus RF Laptimer and PIDFlight Lap. For this project, we will adopt the schematic and use the software and firmware of PIDFlight Lap. However, to keep things simple for now, we will simplify the schematic and use connected mode where the lap timer is connected directly to and powered from a computer or Android phone (via OTG).

Prepare buzzer. The short leg is ground, the long leg is positive. This is also indicated on the top of the buzzer body.

Following the schematic, insert the components to the breadboard

Install Arduino Nano driver

Install Arduino IDE

Install the appropriate firmware.For Chorus RF Laptimer, you can download the Arduino sketch, load it on the Arduino IDE, and upload to the Arduino nano. For PIDFlight Lap, you will get a .hex file and you will need to upload manually. You can use XLoader on Windows or Hex Uploader on the Mac. Or use avrdude directly: